Synthesis of hierarchically porous L-KIT-6 silica–alumina material and the super catalytic performances for hydrodesulfurization of benzothiophene
•A novel material L-KIT-6 was synthesized using solid silica–alumina microspheres.•CoMo/LK catalyst exhibited the highest BT HDS activity among the studied catalysts.•The introduction of LK modulated the morphology of the active metal species.•The synergistic effects of support and active metals improved the catalytic performance.•B acid and the “edge” active centers enhanced the selectivity of DDS route in BT HDS.
A novel micro/mesoporous composite material L-KIT-6 (LK) was successfully synthesized from zeolite L nano-crystals using low cost solid silica–alumina microsphere via two-step hydrothermal crystallization method. LK was used as catalyst support to prepare the hydrodesulfurization (HDS) catalyst. LK micro/mesoporous material and its corresponding catalyst CoMo/LK were characterized using XRD, FTIR, SEM, TEM, N2-adsorption, 27Al MAS NMR, Pyridine-FTIR, H2-TPR, XPS and HRTEM techniques. The physicochemical properties of CoMo/LK were compared with the reference catalysts with different support materials including zeolite L, KIT-6 and γ-Al2O3. The characterization results demonstrated that the textural and acidic properties of the LK composite were dramatically improved comparing with that of zeolite L and mesoporous silica KIT-6. Furthermore, LK had a positive effect on the formation of moderate MoS2 stacking morphology and more “edge” active centers. The catalyst CoMo/LK exhibited a superior catalytic performance for HDS of BT, which could be attributed to the synergistic effects of open porous structure, excellent textural property, appropriate acidity, and MoS2 stacking morphology of CoMo/LK. Moreover, a possible reaction network for BT HDS over CoMo/LK catalyst was proposed.
Graphical abstractMicro/mesoporous composite L-KIT-6(LK) was successfully synthesized using low-cost solid silica–alumina microspheres. The corresponding catalyst CoMo/LK exhibited the highest benzothiophene (BT) hydrodesulfurization (HDS) activity among the studied catalysts. The excellent catalytic performance can be attributed to the synergistic effects of its acidity, textural properties of LK and morphology of the sulfided metal species.Figure optionsDownload full-size imageDownload as PowerPoint slide
Journal: Applied Catalysis B: Environmental - Volume 165, April 2015, Pages 763–773